All tanks will benefit from some type of oxygen exchange (unless you're injecting CO2, different story). Surface area alone doesn't provide for much gas exchange, rather the turbulance on a surface of water will provide the exchange.

On your 10g you specifically mentioned, is there any surface turbulance at all from a HOB filter or anything?

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~Neilan
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YMMV. I do not have an air stone in my 55 or 29 gal tanks. The 55 has a canister so it has no surface disruption. The 29 has a HOB so it has a little there. I have had no issues with skipping the air pump. Although, on my 150T I have to have air stones in the tank with the canisters otherwise the fish are gasping at the surface.

Sounds like the answer is that a air compressor with air stone is not a requirement for any size tank, that the surface area of the water provides for the exchange of gases sufficient for the fish. Having said this, there are circumstances where due to number of fish, or plants, or life that the exchange of gas is not sufficient and a compressor is required. The fish gasping at the surface is the sign that not enough air is present in the water, and time to buy additional capabilities.

Bottom line is that the diver with the head that opens for bubbles is just a tacky tank decoration. Reason enough to get one! Thanks

There's nothing "nature like" in this 10g tank. Too much of a family affair, yet I wouldn't trade this for anything. The kids are as much into it as I. When we learn on this 10g will apply to the 45g soon to come. That big tank will perhaps be more "nature like". Hoping for planted plants, among other things and a school of fish.

Day three and the tank is looking good. Now to go back and review the "cycling a tank" steps to find next items to watch. Also get pictures

lol Truthfully, I like the un-nature like tanks. I like the neon pink and blue gravel with the treasure chest and clam shells that open with air, the pirate that moves around, the glow in the dark novelty rocks, etc.